1. Field of Invention
This invention relates to testable potable water backflow prevention devices and the risk of accidental or intentional contamination to a specific water consumer that these devices pose, by virtue of the differential pressure gradient inherent to these devices, and the ease of access to the potable water supply throughout the differential pressure gradient of these devices. This invention prevents unauthorized access to, use of, or shutoff of a specific users potable water supply.
2. Description of the Prior Art.
Thousands of testable backflow prevention devices have been installed on potable water lines to prevent contamination of public drinking water supplies. Whenever a water consumer creates a cross-connection or potential backflow contamination condition the water consumer is required to install and maintain a backflow prevention device on their water line to prevent contaminated or polluted water from entering the public drinking water supply. The most common location for installation is after the water meter but before any branch piping. These devices are most commonly seen serving high-rise buildings, commercial and industrial facilities, pharmaceutical plants, hospitals, airports, schools, dairies, farms, nursing homes, military bases, bottling plants and restricted access areas.
Testable backflow prevention devices work by means of multiple check valves and zone differential pressure sensing valves. There is a pressure drop, also referred to as head loss, across any check valve assembly that is working properly. Test cocks are located before and after each check valve for testing this differential pressure as well as the ability for the check valves to seal against backflow of water. In most backflow prevention assemblies there are four test cocks. Although these test cocks are intended to be used only for testing the device, and then only by certified technicians, their significance and function is not generally understood; it is common to see hose-bibs and other connections made to the test cocks of these devices. What very few people realize is that there exists a pressure differential across the check valve assembly. It is fairly common to see a hose-bib connection to one of the first test cocks of the device; a connection prohibited by water purveyors. A further problem is the entire device may be by-passed by connection a hose from the first or second test cock to the fourth test cock. Because the hose represents a virtually resistance free route, the water will travel through the by-pass hose and the backflow preventer will no longer be functional. Worse still is the potential for accidental or intentional selective contamination of a specific consumer's water supply. At present, very few, if any, people realize how quickly and easily a specific consumer's water can be contaminated, intentionally or accidentally, through a testable backflow prevention assembly without contaminating the potable water supply at large. This invention is designed to prevent either accidental or intentional contamination of a consumer's water supply and be non-obvious, both visibly and functionally.
A partial search of U.S. Patents in Classes 70, 138, 279 and 285 did not reveal any such device as designed or claimed in my invention. This is not surprising; presently, the hazard is not generally perceived even by those deemed most responsible for or knowledgeable of backflow prevention devices.